Open Doors Don't Invite Criminals

Cambridge, Mass. - LAW enforcement officials, politicians and social scientists have put forward many explanations for the astonishing drop in crime rates in America over the last decade or so, and yet we remain mystified. Studies have shown that while each of the usual suspects -- a decline in crack use, aggressive policing, increased prison populations, a relatively strong economy, increased availability of abortion -- has probably played some role, none has proved to be as dominant a factor as initially suggested.

Perhaps we have been overlooking something obvious -- something that our implicit biases caused us not to notice. My unusual suspect is foreigners: evidence points to increased immigration as a major factor associated with the lower crime rate of the 1990's (and its recent leveling off).

Consider what sociologists call the "Latino paradox": Hispanic Americans do better on a range of various social indicators -- including propensity to violence -- than one would expect given their socioeconomic disadvantages. My colleagues and I have completed a study in which we examined violent acts by almost 3,000 males and females, ranging in age from 8 to 25, from 1995 to 2003. The study selected whites, blacks and Hispanics (primarily Mexican-Americans) from 180 Chicago neighborhoods ranging from highly segregated to very integrated. We also analyzed data from police records, the Census and a separate survey of more than 8,000 Chicago residents who were asked about the characteristics of their neighborhoods.

Surprisingly, we found a significantly lower rate of violence among Mexican-Americans than among blacks and whites. A major reason is that more than a quarter of all those of Mexican descent were born abroad and more than half lived in neighborhoods where the majority of residents were also Mexican. Indeed, the first-generation immigrants (those born outside the United States) in our study were 45 percent less likely to commit violence than were third-generation Americans, adjusting for family and neighborhood background. Second-generation immigrants were 22 percent less likely to commit violence than the third generation.

This "protective" pattern among immigrants holds true for non-Hispanic whites and blacks as well. Our study further showed that living in a neighborhood of concentrated immigration is directly associated with lower violence (again, after taking into account a host of factors, including poverty and an individual's immigrant status).

Now consider that immigration to the United States rose sharply in the 1990's, especially from Mexico and especially to immigrant enclaves in large cities. Overall, the foreign-born population increased by more than 50 percent in 10 years, to 31 million people in 2000. A report by the Pew Hispanic Center found that immigration grew most significantly in the middle of the 90's and hit its peak at the end of the decade, when the national homicide rate plunged to levels not seen since the 1960's. Immigrant flows have receded since 2001, while the national homicide rate leveled off and seems now to be creeping up.

The emerging story goes against the grain of popular stereotypes. Among the public, policymakers and even academics, a common expectation is that a concentration of immigrants and an influx of foreigners drive up crime rates, because of the assumed propensities of these groups to commit crimes and settle in poor, presumably disorganized communities. This belief is so pervasive, studies show, that the concentration of Latinos in a neighborhood strongly predicts perceptions of disorder no matter what the actual amount of crime and disorder.

Yet our study found that immigrants appear in general to be less violent than people born in America, particularly when they live in neighborhoods with high numbers of other immigrants. We are thus witnessing a different pattern from early 20th-century America, when growth in immigration from Europe was linked with increasing crime and formed a building block for what became known as "social disorganization" theory.

In today's world, then, it is no longer tenable to assume that immigration automatically leads to chaos and crime. New York is a magnet for immigration, yet it has for a decade ranked as one of America's safest cities. Border cities like El Paso and San Diego have made similar gains against crime. Perhaps the lesson is that if we want to continue to crack down on crime, closing the nation's doors is not the answer.

Op-Ed Contributor Robert J. Sampson is a professor of sociology at Harvard.